Harvesting Costs Research Articles

Growth performance, biochemical composition and sedimentation velocity of Tetraselmis sp. CTP4 under different salinities using low-cost lab- and pilot-scale systems

Biomass harvesting is one of the most expensive steps of the whole microalgal production pipeline. Therefore, the present work aimed to understand the effect of salinity on the growth performance, biochemical composition and sedimentation velocity of Tetraselmis sp. CTP4, in order to establish an effective low-cost pilot-scale harvesting system for this strain. At lab scale, similar growth performance was obtained in cultures grown at salinities of 5, 10 and 20 g L-1 NaCl. In addition, identical settling velocities (2.4–3.6 cm h-1) were observed on all salinities under study, regardless of the growth stage. However, higher salinities (20 g L-1) promoted a significant increase in lipid contents in this strain compared to when this microalga was cultivated at 5 or 10 g L-1 NaCl. At pilot-scale, cultures were cultivated semi-continuously in 2.5-m3 tubular photobioreactors, fed every four days, and stored in a 1-m3 harvesting tank. Upon a 24-hour settling step, natural sedimentation of the microalgal cells resulted in the removal of 93% of the culture medium in the form of a clear liquid containing only vestigial amounts of biomass (0.07 ± 0.02 g L-1 dry weight; DW). The remaining culture was recovered as a highly concentrated culture (19.53 ± 4.83 g L-1 DW) and wet microalgal paste (272.7 ± 18.5 g L-1 DW). Overall, this method provided an effective recovery of 97% of the total biomass, decreasing significantly the harvesting costs.

Evaluasi Anggaran Biaya Produksi Pada PT. Perkebunan Nusantara III Di Kota Medan

The purpose of this research is to evaluate the production cost budget at PT. Perkebunan Nusantara III This research is a study that uses a qualitative approach with a descriptive method in question is to use information data obtained at the time of the study and from the field in the form of data that is written or oral from the parties involved. The results obtained that PT. Perkebunan Nusantara III has evaluated the calculation of production costs periodically, based on reports based on production prices, selling prices and profit and loss by determining harvest costs, maintenance costs, factory overhead costs, processing costs, and depreciation costs. budget prepared by PT. Perkebunan Nusantara III is not yet perfect enough because there are still many significant deviations both beneficial and adverse. This is the responsibility of managers to conduct more in-depth evaluations to make the realization of costs so as not to occur too far away. Conclusions through field research that PT. Perkebunan Nusantara III has made a production cost budget with a yearly period. PT. Perkebunan Nusantara III has evaluated the calculation of production costs periodically, based on reports based on production prices, selling prices and profit and loss by determining harvest costs, maintenance costs, factory overhead costs, processing costs, and depreciation costs. The budget prepared by PT. Perkebunan Nusantara III is not yet perfect enough.

Методика еколого-економічного оцінювання виробничого навантаження на лісові екосистеми в процесі заготівлі деревини на експорт

Важливим питанням діяльності лісогосподарських підприємств є недопущення негативного впливу на лісові екосистеми або його мінімізація на засадах сталого лісокористування. Встановлено, що екологічно безпечним експортне виробництво лісогосподарського підприємства можна вважати за умов, коли фінансові надходження за реалізацію експортної продукції будуть на рівні, який даватиме змогу відшкодовувати витрати на виробництво і реалізацію експортної продукції, витрати на відтворення лісів, які внаслідок заготівлі (вирубок деревини на експорт) зазнали втрат. Тобто фінансові надходження від реалізації експортної продукції повинні повністю компенсувати виробничі втрати (вилучені деревинні ресурси) в процесі заготівлі внаслідок вирубки лісів. Обґрунтовано, що еколого-безпечна експортна діяльність лісогосподарських підприємств залежить від рівня виробничого навантаження на лісові ресурси. Таке навантаження у процесі заготівлі деревини на експорт виражається у витратах на заготівлю і реалізацію експортної продукції, витратах на ліквідацію (перероблення) додаткових відходів виробництва та на відновлення лісів, а також у втратах від експортного виробництва харчових, кормових, технічних, лікарських та інших лісоресурсів. Запропоновано методику оцінювання експортної діяльності підприємства способом розрахунку показника – коефіцієнта екологічної загрози виробничого навантаження від виробництва експортної продукції. Ця методика дає змогу оцінити стан та рівень загрози лісовій екосистемі для вибору стратегії управління еколого-безпечною експортною діяльністю, адекватної до умов та особливостей конкретного лісогосподарського підприємства.

Evaluating the Most Suitable Tree Species Using Land Expectation Value: A Case Study from Plantation in North of Iran

Plantation in north of Iran is rapidly increasing by local farmers and state but it is not clear which species is most suitable for perpetual timber production. Thus, this study is carried out to evaluate the most suitable timber species among ash (Fraxinus excelsior), elm (Alnus glutinosa), maple (Acer velutinum), oak (Quercus castanifolia), bald cypress (Taxodium distichumin) in north of Iran for evaluation of most suitability using Land Expectation Value (LEV). Data such as wood price at forest road side and variable harvesting cost was collected from secondary souce especially General Office of Natural Resources in Guilan province for a period of 20 years. Average annual increment of different species derived from previous researches. Consumer Price Index (CPI) was used for deflation of stumpage price. Regression analysis was used to predict the stumpage price of different species. Then, the mean price process was determined for different species. Faustmann's formula was used to determine the LEV or Net Present Value (NPV) for a perpetual timber production of different species. The results showed that the LEV of ash, elm, maple, oak and bald cypress were 2623.883, 4653.042, 4319.9644, 2206.8788, 8064.667 (0.33 US dollar/ m3), respectively. The LEV of bald cypress was the highest, so it can be concluded that this species is the most suitable for timber production.

Comparing bags of features, conventional convolutional neural network and AlexNet for fruit recognition

This paper presents a comparative study between Bag of Features (BoF), Conventional Convolutional Neural Network (CNN) and Alexnet for fruit recognition. Automatic fruit recognition can minimize human intervention in their fruit harvesting operations, operation time and harvesting cost. On the other hand, this task is very challenging because of the similarities in shapes, colours and textures among various types of fruits. Thus, a robust technique that can produce good result is necessary. Due to the outstanding performance of deep learning like CNN and its pre-trained models like AlexNet in image recognition, this paper investigates the accuracy of conventional CNN, and Alexnet in recognizing thirty different types of fruits from a publicly available dataset. Besides that, the recognition performance of BoF is also examined since it is one of the machine learning techniques that achieves good result in object recognition. The experimental results indicate that all of these three techniques produce excellent recognition accuracy. Furthermore, conventional CNN achieves the fastest recognition result compared to BoF, and Alexnet.

Assessment of the harvesting costs of different combine harvester fleets

This study discusses practical collection methods of cereal harvesting costs in different agricultural holdings in order to effectively manage combine harvester fleets, make economically reasoned decisions on the exploitation of combine harvesters, reduce harvesting costs and consequently the cost price of cereals. For this purpose, the author used work results of combine harvesters monitored by three randomly selected agricultural holdings, collected practical information on harvesting, analysed this information and provided assessments on the effectiveness of their combine harvester fleet. Evidently, not all combine harvester fleets and combines operate with the same efficiency, as their harvesting costs are different.

A simplified logistics model for integrating BIMAT and IBSAL to estimate harvest costs, energy input and emissions

The Agriculture and Agri-Food’s Biomass Inventory Mapping and Analysis Tool (BIMAT) provides internet-based GIS functionality to query and visualize biomass inventory data in Canada. The Integrated Biomass Supply Analysis and Logistics (IBSAL) model is a modularized simulation of biomass supply chain. In this study, IBSAL modules are assembled to simulate harvesting of straw, stover, and switchgrass yields. The operations in this study started from combining for grain crop residues and ended in stacking bales on the field side. The equation C=aR^b Y^c was fitted to the simulated data to estimate constants a, b, and c for cost in $/dry tonne, energy input in MJ/dry tonne, and carbon emissions in kg CO2/dry tonne. Variable R is the fraction of above ground biomass removed during harvest and Y is the yield defined as biomass above ground (dry tonne/ha). These functions are supplied to the BIMAT portal and developed specific values for costs, energy input, and emissions on the map. The farm gate cost cost for the stacked bales ranged from $20 per dry tonne for high yielding regions of southwest Edmonton and Ontario to $27 per dry tonne for the eastern Ottawa region, and $31 per dry tonne for low yielding regions of central Saskatchewan. The costs are validated with published custom rates. It is recommended that the next step is to integrate IBSAL and BIMAT codes so the logistics values are generated and shown automatically on the map.

A Brief Review of Anaerobic Digestion of Algae for Bioenergy

The potential of algal biomass as a source of liquid and gaseous biofuels has been the subject of considerable research over the past few decades, with researchers strongly agreeing that algae have the potential of becoming a viable aquatic energy crop with a higher energy potential compared to that from either terrestrial biomass or municipal solid waste. However, neither microalgae nor seaweed are currently cultivated solely for energy purposes due to the high costs of harvesting, concentrating and drying. Anaerobic digestion of algal biomass could theoretically reduce costs associated with drying wet biomass before processing, but practical yields of biogas from digestion of many algae are substantially below the theoretical maximum. New processing methods are needed to reduce costs and increase the net energy balance. This review examines the biochemical and structural properties of seaweeds and of microalgal biomass that has been produced as part of the treatment of wastewater, and discusses some of the significant hurdles and recent initiatives for producing biogas from their anaerobic digestion.

Optimization of thermal pre‐flocculation treatment for effective air flotation harvesting of microalgae

AbstractBACKGROUNDThe production of microalgal biomass as a potential biofuel source is limited by expensive harvesting costs. However, air flotation has been applied as an effective method for harvesting microalgal cells from diluted liquid suspensions. In this study, Chlorella vulgaris and Scenedesmus obliquus harvesting experiments were performed with thermal pretreatment prior to air flotation.RESULTSAn orthogonal test showed that the harvesting efficiency was affected by the heating temperature and pH but not by the microalgal concentration or stirring rate. Under a heating temperature of 90 °C and pH 3, the optimal heat‐aided air flotation efficiency achieved for harvesting C. vulgaris was 26.5%, with a concentration factor of 5.5. For harvesting S. obliquus, the optimal harvesting efficiency was 93.6% and the concentration factor was 25.0 under a heating temperature of 70 °C and pH 3.CONCLUSIONHigh temperature and low pH increased the zeta potential value of the microalgal cell surface, and high temperature promoted the secretion of extracellular organic matter, causing microalgal cells to gather and form flocs. The smaller flocs and higher zeta potential value of S. obliquus led to its higher harvesting efficiency. These conditions provided the possibility of waste acidic gas and thermal energy from industries replacing flocculants for the harvesting process. © 2019 Society of Chemical Industry

Optimization of Skid Trails and Log Yards on the Amazon Forest

Research highlights: We used Dijkstra Algorithm (DA) to define optimal allocation of yards in order to minimize total skid-trail’s distance in the Amazon Forest. DA minimized trails’ distances and associated transportation costs, leading to an even smaller value when the current planning was disregarded and suggesting the reduction of deleterious environmental externalities. Background and objectives: We sought to answer if it is possible to optimize distances and intrinsic costs in the management of Amazonian forests using DA. The objective was to minimize skid trails distances by best allocating yards using DA and to compare four scenarios of forest harvest planning in the Brazilian Amazon. Materials and methods: Tree census data from Gênesis-Salém Farm, state of Pará, Brazil, were used. The yards and roads located by Grupo Arboris (scenario 1) were compared to three alternative scenarios in terms of total skid distance, trails and road densities, and skidding costs for three successive harvests, seeking to minimize total skid-trails’ distance. Alternative scenarios were to keep the number of yards within work units (WU) and place them in the edge of existing roads (scenario 2); keep the number of yards within each WU (scenario 3); and place 23 yards, disregarding the current planning (scenario 4). Results: Total skid-trail’s distance, number of trees above optimal extraction distance and densities of skid trails and roads were smaller in scenarios 2, 3, and 4, compared to the current yard allocation (scenario 1). Scenario 4, with fewer restrictions, reduced skid-trails’ distances by 23%. Harvest costs decreased from scenario 1 to 4 in all three harvest cycles. Conclusions: DA allowed optimized distribution of yards and skid trails and generated efficient results for harvest planning. This reinforces the importance of optimized planning, which establishes satisfactory results in the effort to reduce costs and environmental impact keeping high efficiency.

Solar concentrator based multipurpose sunlight harvesting system without tracking

Sunlight is being utilized to reduce energy crisis and it is a popular and reliable source of energy because of its pollution free nature. It is abundantly available on the Earth but difficult to achieve maximum efficiency during daytime without tracking. We have designed and developed a non-tracking solar concentrator system based on a combination of large Fresnel lens and segmented mirrors. Six segmented mirrors are mounted at different angles so that the concentrated light due to the Fresnel lens is redirected into a particular area throughout the day to achieve maximum concentration without tracking the sun. The entire system is mounted in a single mechanical mount with no moving parts. The concentrated sunlight was utilized for multipurpose solar applications. We have demonstrated simultaneous solar water heating and electricity generation by means of a thermoelectric generator (TEG) module using the developed system. The maximum temperature of water recorded at the outlet from the water heating system is 88°C and efficiency at this temperature is 0.47. The preliminary results of power generated from one TEG module is 40 mW. Experimental results of water heating throughout the day and electricity generation using TEG is reported. This type of system is unique, robust, and low cost for sunlight harvesting.

The potential of a natural biopolymeric flocculant, ε-poly-L-lysine, for harvesting Chlorella ellipsoidea and its sustainability perspectives for cost and toxicity.

The successful production of microalgal biomass requires the precise coordination of many different steps. Cell harvesting is a central process in all methods currently used for the production of microalgal biomass. Therefore, improving the harvesting process itself, and using a harvesting method that is compatible with adjacent steps, is necessary to prevent problems that may occur during downstream processing. This study examined the potential of the cationic biopolymer ε-poly-L-lysine (ε-PLL) for use in the harvest of microalgae (Chlorella ellipsoidea). The effects of ε-PLL concentration and mixing intensity on flocculation efficiency and operating costs were determined. We found that ε-PLL was not toxic to microalgal cells at concentrations of up to 25mg/L, based on the photosystem II quantum yield. A recovery rate of 95% was achieved using 19mg/L ε-PLL, and the estimated harvest cost was 20 US$/ton of harvested biomass. Moreover, ε-PLL displayed antimicrobial properties, leaving the harvested biomass intact and pure. Therefore, the use of ε-PLL-induced flocculation appears to be an attractive option when harvesting microalgal biomass for use as low- and high-value commodities for humans or animals.

Techno-economic assessment of corn stover for hybrid bioenergy production: A sustainable approach

Corn stover (CS) contains high moisture in the fall and farmers keep it unharvested until next spring for its natural drying. CS contains 70% more carbon than other grain crop residues. Farmers traditionally use a portion of CS for livestock bedding and cattle feed but the rest is kept unharvested. Potential soil erosion, carbon sequestration, and nutrient removal concerns might be considered before CS harvesting. Hydrothermal carbonization (HTC) of wet biomass can produce energy dense solid bio-carbon. Hydrothermal process water (HTPW) can produce energy and recover nutrient in anaerobic digestion (AD). This study reported the results of various experiments performed on non-rooted fall harvested CS of an Ontario farm. Ontario CS was finally assessed for techno-economic and environmental aspects. This research showed 78% energy and a portion on nutrients as liquid bio-fertilizer of fall harvested CS are recoverable. Corn roots with 6–10 cm stalks, cobs and husks can be kept in the soil to recover soil organic matter (SOM) and protection of soil erosion. The process indicates the sustainable CS harvesting in the fall with possibility to reduce 75% of existing harvesting cost and reduction of greenhouse gas (GHG) emission.

Efficient membrane microalgal harvesting: Pilot-scale performance and techno-economic analysis

In this study, a pilot-scale ultrafiltration membrane system was developed for harvesting of oleaginous Scenedesmus acuminatus by adjusting transmembrane pressure-TMP (cross flow velocity-CFV changed accordingly) and applying air-assisted backwashing technology to increase membrane flux, reduce flux declining rate and enhance flux recovery rate. A two-stage harvesting strategy (normal filtration–strengthening concentration) was performed for harvesting of 53 m3 of S. acuminatus suspension to achieve both high flux and concentration factor. The results showed that TMP (CFV) had positive impact on average flux, and the increase could effectively overcome the decrease in average flux when harvesting microzooplankton contaminated S. acuminatus culture. Shortening the interval of air-assisted backwashing to 15 min enhanced the average flux up to 12%. The average flux decreased with the increased loading volume, and volumetric reduction factor had a negative effect on average flux. For the harvesting of 53 m3 of S. acuminatus suspension, an average membrane flux reached up to 53.6 L/(m2·h), with a concentration factor of 145, a final dry weight of 136 g/L, and a biomass recovery of 93% after backwashing. Techno-economic analysis for annual harvesting capacity of 10000 t dry biomass showed that the total harvesting cost was $0.30/kg dry microalgal biomass with a volumetric reduction factor of 50, and membrane harvesting under CFV of 0.5–0.6 m/s may lead to a moderate flux of 60–66.6 L/(m2·h) and minimal total cost of $0.27/kg dry biomass based on the sensitivity analysis. The results of this study suggest that this clean and efficient ultrafiltration membrane approach has high industrialization potential.

Shifting from even-aged management to less intensive forestry in varying proportions of forest land in Finland: impacts on carbon storage, harvest removals, and harvesting costs

Many studies have reported increased multi-functionality and financial profits due to a shift from even- to uneven-aged forest management. However, little is known (from long-term experiences or predictions) how alternative management systems could affect national-scale wood production and carbon storage, if adopted over very large areas. We analysed these effects using an area-based framework, in which multiple Markov chain models were used to simulate the development of forests according to different management systems. Classification of forests to wood availability categories was used to determine the system to be applied. We enhanced the framework to allow shifts between management systems that correspond to enforced or voluntary changes in forest use. Simulations of extensive shifts from conventional even-aged management to alternative silvicultural systems revealed interesting developmental patterns that cannot be directly deduced from studies that upscale from smaller areas. Our results show that the amount of carbon stored by Finnish forests can be increased by applying less intensive management systems, although this has trade-offs in terms of harvests and associated financial costs. The level of trade-offs differed depending on the type of forest that shifted between management systems and whether areas were also assumed to be completely set aside from forestry. These differences were further pronounced if the desired harvest levels and their allocation changed along with the management system. If the studied attributes were considered at the same relative scale and with equal weighting, the extensive shifts to alternative management systems exhibited the strongest impact on harvesting costs.

Development of Stirling Pump mechanism for Irrigation in remote rural farms

Inadequate supply of safe water, the requirement of food exports, Low GDP creates a scenario where 26% of the population in the Sub-Saharan Africa suffer from food insecurity. Cultivation of food locally is necessary to drive the cost of food down. This can be done using the abundant groundwater source in the region, however, the energy cost of harvesting the water supply is very high and hence not presently utilised. While solar PV technology is readily available, PV solutions are much too expensive for small scale rural farmers. This research aims at developing a solar thermal powered Stirling pump that can be produced locally, using local resources to reduce irrigation costs and provide income, food and energy security in the region, by promoting independent farming through small-scale farms. In order to develop the Stirling pump, a Low Temperature Differential (LTD) Stirling engine has been modelled in 3D, simulated and investigated with the help of Computational Fluid Dynamics with ANSYS 16.1 software. The Analysis is aimed at obtaining a true representation of the pressure, temperature and compression ratio that dictate the functioning of a Gamma type Stirling engine. This model developed can then be modified and improved upon to further boost the performance of the Stirling Engine to be integrated with a water pumping system to extract ground water for irrigation purposes.

Algal biofilm ponds for polishing secondary effluent and resource recovery

In order to reduce the cost of microalgae harvesting, biofilm algal cultivations have received attention as a potential platform for algal biomass production and wastewater treatment. Two 50-L ponds containing vertically oriented geotextiles, cotton textiles, and polyethylene sheets were fed secondary effluent to examine the growth of algal biofilms. The removal of total phosphorus, PO43−-P and NO3−-N ranged from 52 to 97%, 59 to 93%, and 0 to 99%, respectively. The highest biomass productivity was 1.4 and 0.5 g m−2 day−1, and the lipid content of the attached biomass was quite low, 0.36 and 0.48%, in the cotton textile and polyethylene-baffled pond, respectively. The lipid content of the suspended biomass of the cotton textile and polyethylene pond was very low and similar (0.5%), but it increased to 13.8 and 3.4%, respectively, after a starvation period of 13 days.

Novel extracting methods for conifer stumps

ABSTRACTStumps can play an important role in providing a renewable raw material for energy generation or biorefining. Currently, it is an underutilized resource in the Scandinavian countries because of the high harvesting cost and contaminant problems of the raw material produced. The objectives of this study were: (1) to evaluate the efficiency and functionality of a forwarder-based stump extraction device that splits and vibrates the stump during lifting, (2) to evaluate the efficiency and functionality of a crawler excavator-based stump lifting device that cuts off the lateral roots and lifts the stump, and (3) to create time consumption models for the aforementioned stump extraction systems based on field studies. Both stump extraction devices operated without any unnecessary delays, as there were no breakdowns but the effective stump harvesting time of the crawler excavator-based extraction device was markedly lower than the time taken by the forwarder-based extraction device. Compared to previous studies, the efficiency of the studied devices (expressed as time consumption per harvested stump) was not competitive relative to the conventional method, in which a crawler excavator is equipped with a stump extraction head that breaks up and lifts the stump and the lateral root system completely.

Birch shelterwood removal – harvester and forwarder time consumption, damage to understory spruce and net revenues

ABSTRACTTo improve the micro climate for Norway spruce (Picea abies (L.) Karst.) regeneration and achieve higher growth, a system of birch shelterwoods with naturally regenerated birch (Betula spp.) creating an overstory sheltering planted spruce is implemented in southern Sweden. Even though the primary objective is to establish a new spruce stand, the economic viability depends on efficient birch overstory harvest with little damage to spruce regeneration. This study aimed to analyze time consumption and net revenues for harvester and forwarder work when removing the birch overstory, and to describe the frequency of logging damage in the residual spruce stand. Time consumption data was collected through time studies of harvesting and forwarding of 10 study plots. Sample plots were inventoried after harvesting and forwarding operations to identify damage on the residual spruce. Average harvester productivity was 2.8 oven dry ton per efficient work hour. The variation in time consumption was up to 94%, explained by a positive correlation with the number of trees harvested per hectare and a negative relationship with removed volume per hectare. Forwarder loading time correlated with forwarded volume along the strip road and the number of birch trees per ha prior to logging. Approximately 7–17% of the residual trees were damaged, and the harvester caused 83% of the damage. Due to high harvesting costs and low revenues, only plots with large removals provided positive net revenues. Birch shelterwoods can therefore not be expected to increase net revenues but are best seen as a regeneration method for addressing stand re-establishment challenges.

Impacts of silvicultural prescriptions and implementation of best management practices on timber harvesting costs

ABSTRACTRising costs of forest operations and decreasing revenue generated from harvesting are becoming critical challenges in forest management throughout the Northeastern US. Along with this, the low markets for comminuted forest residues and stricter policies on environmental protection have prompted utilization of these materials as slash mats on skid trails for minimizing soil disturbances. The aim of this study was to evaluate the cost of different silvicultural treatments and utilization of forest residues generated from a mechanized timber harvesting operation for implementing Best Management Practices (BMPs). The field-based experiment was done in central Maine, where four forest stands were managed at varying intensities following silvicultural prescriptions common to the region (partial harvest (PH) and clear-cut (CC) treatments). Variables measured included delay-free cycle times of various timber harvesting machines, predictor variables, and stand features. The total cost of PH was higher than that of CC ($22.94 m−3 versus $14.88 m−3). Of the various operational phases, the costs associated with skidding was the highest and ranged from 52 to 70% of the total cost for PH and CC, respectively. The cost of BMP implementation was estimated to be between $10 and $52 PMH−1 or $1.0 and $3.7 m−3, and was influenced by several factors, including machine maneuverability and the extent of area which demanded BMP implementation. This information on the cost and productivity for timber harvesting operations, along with BMP implementation, will support the development of economic and environmentally sustainable harvesting strategies.